International laboratories for Kaonic atoms and nuclei

• GSI-HADES (Darmstadt, GSI)
  
  HIGH ACCEPTANCE DI-ELECTRON SPECTROMETER
  http://www-hades.gsi.de/
  HEP articles associated with GSI-HADES
  HADES
  GSI-HADES (Darmstadt, GSI)
  HIGH ACCEPTANCE DI-ELECTRON SPECTROMETER
  
  Spokesperson: Salabura, Piotr
  Contact Email: salabura@psja1.if.uj.edu.pl
  URL: http://www-hades.gsi.de/
  
  A High Acceptance DiElectron Spectrometer (HADES) is a second generation experiment being under construction at GSI SIS facility in Darmstadt (Germany). Its scientific program includes studies of in-medium properties of hadrons in hadronic matter and electromagnetic structure of hadrons. As a tool for such investigations dilepton spectroscopy after heavy ion and pion induced reactions has been proposed. A major part of HADES physics program is focusing on the exiting suggestion that modifications of the vector meson masses inside nuclear matter could be a signal for QCD chiral symmetry restoration.The chiral symmetry is one of the fundamental symmetries of QCD in the limit of massless quarks. It implies a complete decupling of left- and right-handed particles. In the ground state, this symetry is spontaneously broken which is manifested in the mass spectrum of light mesons. Calculations in the Nambu-Jona-Lasinio (NJL) model predict a partial restoration of chiral symmetry at increased bayron density and tempetature, the restoration will lead to a decrease of the constituent quark masses which might affect the hadron masses when determined in a dense medium. The model calculations predict substantial effects at the large densities(three times the nuclear density) reached in the central reaction zone of heavy-ion collisions at SIS energies. The most suitable probes for possible mass changes are the light vector mesons, in particular the ro and omega mesons, since there exists a decay branch into electron positron pairs which escape from the hadronic matter with negligible final state interaction. The invariant mass spectrum of the pairs represents a direct measurement of the in-medium masses.

• FRASCATI-DAFNE-SIDDHARTA
  Silicon Drift Detectors for Hadronic Atom Research by Timing Application
  http://www.lnf.infn.it/esperimenti/siddharta
  HEP articles associated with FRASCATI-DAFNE-SIDDHARTA
  SIDDHARTA

The objective of the SIDDHARTA (Silicon Drift Detector for Hadronic Atom Research by Timing Application) experiment is to continue, to deepen and enlarge the successful scientific line, initiated by the DEAR (DAFNE Exotic Atoms Research) experiment in performing precision measurements of X-ray transitions in exotic (kaonic) atoms at DAFNE.

A new class of precision measurements of the strong interaction effects in elementary systems like exotic hadronic atoms can be opened by the use of a detection apparatus based on large area Silicon Drift Detectors (SDD) with good energy and time resolution to detect X rays. Understanding low-energy strong interaction dynamics is made possible by the study of elementary exotic systems formed by a hadron negatively charged, like a pion, a kaon, an antiproton or a sigma hyperon, orbiting around a nucleus of hydrogen, deuterium, helium. The measurement at the percent level of strong interaction effects in these exotic atoms allows to explore sectors of non-perturbative QCD missing of experimentally determined quantities. Among these, a crucial role is played by the so called meson-nucleon sigma terms. The cleanest way to determine the antikaon-nucleon isospin dependent scattering lengths, from which the sigma terms can be determined, is the measurement of the x-ray transitions to the ground state in the exotic atoms kaonic hydrogen and kaonic deuterium. In these experiments, the shift of the K_a lines from the purely electromagnetic calculated values, due to the strong interaction, and the broadening of the line, are measured. Then the scattering lengths are determined from these quantities in a direct and precise way, via the Deser–Trueman relations.

The project intends to develop spectroscopic SDDs and enlarge the field of these detectors in triggered applications. The kaon facility of the DAFNE collider in Laboratori Nazionali di Frascati can be substantially improved, percent level measurements in a high background environment becoming possible. Kaons are generated by f(1020)-decay. The high luminosity (10³²cm^-2s^-1), low momentum (127 MeV/c), low momentum spread (0.1%), low pion contamination, makes DAFNE a unique tool for the study of exotic atoms.

• FRASCATI-DAFNE-DEAR (Frascati)
  DAFNE EXOTIC ATOMS RESEARCH AT THE FRASCATI PHI-FACTORY
  http://www.lnf.infn.it/esperimenti/dear/
  HEP articles associated with FRASCATI-DAFNE-DEAR
  DEAR

Spokesperson: Guaraldo, Carlo
Contact Email: Carlo.Guaraldo@lnf.infn.it
URL: http://www.lnf.infn.it/esperimenti/dear/

DEAR (DAFNE Exotic Atoms Research) is an experiment devoted to a precision measurement of the scattering lengths of the kaon-nucleon system, through a percent measurement of the Kalpha line shifts - due to strong interaction - in kaonic hydrogen and kaonic deuterium. In addition to the precise determination of low-energy parameters, a fundamental non-perturbative QCD quantity, such as the KN sigma term, undetermined up to now, will be measured. The sigma term is a quantity which gives an indication of the chiral symmetry breaking part in the total Hamiltonian for a nucleon state. Moreover, the KN sigma term is an extremely sensitive and direct measurement of the strangeness content of the proton. One can eventually extract the KN sigma term from accurate measurements of K- nucleon amplitudes at zero energy. This will be possible only with the DEAR experiment. DAFNE is a unique source of low momentum, monochromatic (127 MeV/c) K-, coming from the decay of the phi(1020) meson produced by the e+e- interactions. In the DEAR experimental set-up the K-, after being slowed down, stop inside a low temperature (25 K), pressurized (3 bar) gaseous hydrogen target and eventually form an exotic K-hydrogen atom in a high excited atomic level, which subsequently decays to the ground level, emitting characteristic X-rays. The selected conditions for the density of the hydrogen target reduce the Stark mixing and hence enhance the yield of the 2P-1S X-ray transition. The X-ray detectors will be CCD (Charge Coupled Devices), which offer high resolution and efficiency (140 eV and 60%, respectively, at 6.5 KeV), and, above all, unprecedented background suppression of ionizing particles, neutrons and gammas.

• SATURNE-213 (Saclay)
  MEASUREMENT OF SPIN DEPENDENT OBSERVABLES IN THE REACTION P P --> P K+ Y*
  http://www.to.infn.it/activities/experiments/disto/disto.html
  HEP articles associated with SATURNE-213
  DISTO

• FRASCATI-DAFNE-FINUDA (Frascati)
  A DETECTOR FOR NUCLEAR PHYSICS AT DAFNE
  http://www.lnf.infn.it/esperimenti/finuda/finuda.html
  HEP articles associated with FRASCATI-DAFNE-FINUDA
  FINUDA

• JPARC-E-016 (J-PARC)
  Electron pair spectrometer at the J-PARC 50-GeV PS to explore the chiral symmetry in QCD
  
  Spokesperson: Yokkaichi, S.
  
  HEP articles associated with JPARC-E-016
  Collaboration members in HepNames

• AMADEUS
• LEAR
• KLOE
• ...